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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>后代选择器</title>
    <style>
        div span{
            color: aqua;
        }
    </style>
</head>
<body>
    <span>span标签</span>
    <div>
        <span>div的儿子span标签</span>
        <p>
            <span>div的孙子</span>
        </p>
    </div>

</body>
</html>